Compositions and uses thereof

ABSTRACT

A silicon-carbon particulate composite suitable for use as active material in a negative electrode of a Li-ion battery, a precursor composition comprising the silicon-carbon particulate composite, a negative electrode comprising the silicon-carbon particulate composite and/or precursor composition, a Li-ion battery comprising the negative electrodes, a method of manufacturing the silicon-carbon particulate composite, precursor composition, negative electrode and Li-ion battery, the use of the silicon-carbon particulate composite in a negative electrode of a Li-ion battery to inhibit or prevent silicon pulverization during cycling, for example, during 1st cycle Li intercalation or de-intercalation and/or to maintain electrochemical capacity after 100 cycles, and a device, energy storage cell, or energy storage and conversion system comprising the silicon-carbon particulate composite and/or precursor composition.

TECHNICAL FIELD

The present invention is directed to a silicon-carbon particulatecomposite suitable for use as active material in a negative electrode ofa Li-ion battery, to a precursor composition comprising thesilicon-carbon particulate composite, to a negative electrode comprisingthe silicon-carbon particulate composite and/or precursor composition,to a Li-ion battery comprising the negative electrodes, to a method ofmanufacturing the silicon-carbon particulate composite, precursorcomposition, negative electrode and Li-ion battery, to the use of thesilicon-carbon particulate composite in a negative electrode of a Li-ionbattery to inhibit or prevent silicon pulverization during cycling, forexample, during 1st cycle Li intercalation or de-intercalation and/or tomaintain electrochemical capacity after 100 cycles, and to a device,energy storage cell, or energy storage and conversion system comprisingthe silicon-carbon particulate composite and/or precursor composition.

BACKGROUND

Metals forming compounds or alloys with lithium exhibit very highspecific charge in the negative electrode in lithium ion batteries. Forexample, the theoretical specific charge of silicon metal electrodes canbe up to 4,200 mAh/g. However, silicon particles can crack owing to thelarge volume expansion of silicon when inserting lithiumelectrochemically (i.e., during lithium intercalation andde-intercalation). This cracking problem is known as siliconpulverization. Further, the creation of new surfaces during particlecracking can lead to excessive electrolyte decomposition andde-contacting of the silicon from the electrode. Silicon pulverizationmanifests as specific charge losses after several charge/dischargecycles as well as irreversible capacity during first cycle charge anddischarge and, in general, poor cycle stability. These are significantlimitations that have delayed the adoption of silicon-based activematerials in commercial lithium-ion batteries.

There is ongoing need to develop new silicon active materials forelectrode materials which address the problem of silicon pulverizationand the concomitant cycling stability problems.

SUMMARY OF THE INVENTION

A first aspect of the present invention is directed to a silicon-carbonparticulate composite suitable for use as active material in a negativeelectrode of a Li-ion battery, having one or more of:

-   -   (i) microporosity of at least 5.0%, optionally no greater than        about 25.0%,    -   (ii) a BJH average pore width of less than about 250 Å, and    -   (iii) a BJH volume of pores of from about 0.05 cm³/g to about        0.25 cm³/g.

A second aspect of the present invention is directed to a precursorcomposition for a negative electrode of a Li-ion battery, the precursorcomposition comprising a silicon-carbon particulate composite accordingto first aspect, comprising a further carbonaceous particulate,optionally wherein the further carbonaceous particulate comprises atleast two different types of carbonaceous particulate.

A third aspect of the present invention is directed to a negativeelectrode comprising a silicon-carbon particulate composite according tothe first aspect.

A fourth aspect of the present invention is directed to a negativeelectrode comprising a precursor composition according to the secondaspect.

A fifth aspect of the present invention is directed to a Li-ion batterycomprising an electrode according to third or fourth aspect.

A sixth aspect of the present invention is directed to a Li-ion batterycomprising a negative electrode which comprises a silicon-carbonparticulate composite, wherein silicon pulverization does not occurduring 1st cycle lithium intercalation and de-intercalation and/orwherein electrochemical capacity is maintained after 100 cycles.

A seventh aspect of the present invention is directed to a method ofmaking a silicon-carbon particulate composite, comprising co-millingsilicon and carbonaceous starting materials under wet conditions toproduce a silicon-carbon particulate composite having a nanostructurewhich inhibits or prevents silicon pulverization when used as activematerial in a negative electrode of a Li-ion battery and/or whichmaintains electrochemical capacity of a negative electrode.

An eighth aspect of the present invention is directed to a method ofpreparing a precursor composition for a negative electrode of a Li-ionbattery, comprising preparing, obtaining, providing or supplying asilicon-carbon particulate composite according to first aspect orobtainable by a method according to the seventh aspect, and combiningwith a further carbonaceous particulate.

A ninth aspect of the present invention is directed to a method ofpreparing a precursor composition for a negative electrode of a Li-ionbattery, comprising, preparing, obtaining, providing or supplying acarbonaceous particulate and combining with a silicon-carbon particulatecomposite according to first aspect or obtainable by a method accordingto the seventh aspect.

A tenth aspect of the present invention is directed to a method ofpreparing a precursor composition for a negative electrode of a Li-ionbattery, comprising combining a silicon-carbon particulate compositeaccording to first aspect or obtainable by a method according to theseventh aspect with a further carbonaceous particulate.

An eleventh aspect of the present invention is directed to a method ofmanufacturing a negative electrode for a Li-ion battery, comprisingforming the negative electrode from a precursor composition according tothe second aspect or obtainable by a method according to any one ofeighth, ninth or tenth aspects, optionally wherein the precursorcomposition comprises additional components or is combined withadditional components during forming, optionally wherein the additionalcomponents include binder.

A twelfth aspect of the present invention is directed to the use of asilicon-carbon particulate composite as active material in a negativeelectrode of a Li-ion battery to inhibit or prevent siliconpulverization during cycling, for example, during 1st cycle Liintercalation or de-intercalation and/or to maintain electrochemicalcapacity after 100 cycles.

A thirteenth aspect of the present invention is directed to the use, asactive material in a negative electrode of a Li-ion battery, of asilicon-carbon particulate composite according to the first aspect, forimproving cycling stability of the Li-ion battery compared to a Li-ionbattery which comprises an active material which is a mixture of siliconparticulate and carbonaceous particulate which is not a composite and/ordoes not have a nanostructure which inhibits or prevents siliconpulverization during cycling, for example, during 1st cycle Liintercalation, and/or which is not prepared by co-milling and/or doesnot have a nanostructure which maintains electrochemical after 100cycles.

A fourteenth aspect of the present invention is directed to the use of acarbonaceous particulate material in a negative electrode of a Li-ionbattery, wherein the electrode comprises a silicon-carbon particulatecomposite according to the first aspect.

A fifteenth aspect of the present invention is directed to a devicecomprising the electrode according to the third and/or fourth aspect, orcomprising a Li-ion battery according to the fifth and/or sixth aspect.

A sixteenth aspect of the present invention is directed to an energystorage cell comprising a silicon-carbon particulate composite accordingto the first aspect or a precursor composition according to the secondaspect.

A seventeenth aspect of the present invention is directed to an energystorage and conversion system comprising a silicon-carbon particulatecomposite according to the first aspect or a precursor compositionaccording to the second aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a SEM picture of Nano-composite 1 prepared according to theExamples.

FIG. 1B is a SEM picture of Nano-composite 3 prepared according to theExamples.

FIG. 2 is a graph depicting pore size distributions of Nano-composites1, 2 and 3 prepared according to the Examples.

FIG. 3 is a graph showing the cycling performance of a negativeelectrode made from Dispersion formulation A (black filled circles),Dispersion formulation B (grey filled circles) and Dispersionformulation C (open circles).

FIG. 4 shows the 1^(st) cycle lithium intercalation (black curves) andde-intercalation (gray curves) of a negative electrode made fromDispersion formulation A (FIG. 4A), Dispersion formulation B (FIG. 4B)and Dispersion formulation C including the commercial Si-particulate(FIG. 4C).

DETAILED DESCRIPTION OF THE INVENTION

It has surprisingly been found that by controlling the nanostructure andmorphology of a silicon-carbon particulate, by co-milling silicon andcarbonaceous starting materials under conditions which promote theformation of said nanostructure and morphology, produces a compositematerial that exhibits Si-nanodomains in close contact to conductivecarbon in a three-dimensional network-like structures which are wellsuited to accommodate the large volume change that occurs withlithium-intercalation and de-intercalation in a negative electrodes of aLi-ion battery. More particularly, the silicon-carbon particulateinhibits or mitigates silicon pulverization during electrochemicallithium insertion/extraction and de-contacting effects which can occurwith such large volume changes, by reducing the extent of the volumechange and/or by providing sufficient pore void space to betteraccommodate said volume expansion during lithiation, thus improvingcycling stability and/or reducing capacity losses during cycling of theLi-ion battery. Contact between nano-Si domains also remains favorablebecause of the three-dimensional network-like structure of thesecomposites, as opposed to one-dimensional nano-Si morphologies (e.g.Si-nanotubes or nanowires) that upon breakage at a single point resultin de-contacted nano-Si structures.

The silicon-carbon particulate composite suitable for use as activematerial in a negative electrode of a Li-ion battery has one or more of:

-   -   (i) microporosity of at least 5.0%, optionally no greater than        about 25.0%,    -   (ii) a BJH average pore width of less than about 250 Å, and    -   (iii) a BJH volume of pores of from about 0.05 cm³/g to about        0.25 cm³/g.

By “silicon-carbon particulate composite” is meant a particulatecomposite in which individual particles have a morphology other than aone-dimensional morphology such as nanotubes or nanowires.

By “microporosity” is meant the % of external surface area of microporesin relation to the total BET specific surface area of the particulate.As used herein, a “micropore” means a pore width of less than 20 Å, a“mesopore” means a pore width of from 20 Å to 500 Å, and a “macropore”means a pore width of greater than 500 Å, in accordance with the IUPACclassification.

In certain embodiments, the silicon-carbon particulate composition hasone or more of:

-   -   (i) a microporosity of from about 5.0% to about 20%,    -   (ii) a BJH average pore width of from about 50 Å to about 200 Å,        and    -   (iii) a BJH volume of pores of at least about 0.10 cm³/g

In certain embodiments (which may be referred to as Embodiment A), thesilicon-carbon particulate has one or more of:

-   -   (i) a microporosity of from about 5% to about 20%, for example,        from about 8-17%    -   (ii) a BJH average pore width of from about 75 Å to about 150 Å,        for example, from about 100-150 Å, and,    -   (iii) a BJH volume of pores of at least about 0.50 cm³/g, for        example, from about 0.50 cm³/g to about 1.25 cm³/g.

In such embodiments, the microporosity may be from about 10-20%, or fromabout 12-18%, or from about 13-17%, the BJH average pore width may befrom about 100 Å to about 150 Å, or from about 120-150 Å, or from about120-140 Å, and the BJH volume of pores may be at least about 0.75 cm³/g,for example, from about 0.75-1.25 cm³/g, or from about 0.90-1.10 cm³/g.

In such embodiments, the microporosity may be from about 5-15%, or fromabout 7-13%, or from about 8-11%, the BJH average pore width may be fromabout 75 Å to about 135 Å, or from about 90-120 Å, or from about 100-120Å, and the BJH volume of pores may be at least about 0.60 cm³/g, forexample, from about 0.70-1.10 cm³/g, or from about 0.80-1.00 cm³/g.

In certain embodiments (which may be referred to as Embodiment B), thesilicon-carbon particulate has one or more of:

-   -   (i) a microporosity of from about 5% to about 15%, for example,        from about 10-15%    -   (ii) a BJH average pore width of from about 100 Å to about 180        Å, for example, from about 130 Å to about 150 Å, and    -   (iii) a BJH volume of pores of at least about 0.10 cm³/g, for        example, from about 0.10 cm³/g to about 0.25 cm³/g.

In such embodiments, the microporosity may be from about 8-17%, or fromabout 10-15%, or from about 11-14%, the BJH average pore width may befrom about 120 Å to about 160 Å, or from about 125-150 Å, or from about135-145 Å, and the BJH volume of pores may be at least about 0.12 cm³/g,for example, from about 0.12-0.18 cm³/g, or from about 0.90-1.10 cm³/g.

In certain embodiments, the silicon-carbon particulate at least two of(i), (ii) and (iii), for example, (i) and (ii), or (ii) and (iii), or(i) and (iii). In certain embodiments, the silicon-carbon-particulatehas each of (i), (ii) and (iii).

In certain embodiments, the silicon-carbon particulate composite may befurther characterized in having:

-   -   (1) a BET specific surface area (SSA) equal to or lower than        about 400 m²/g; and/or    -   (2) an average particle size of from about 50-2000 Å.

In certain embodiments, the silicon-carbon particulate composite has anaverage particle size of from about 50-1750 Å, or from about 50-1500 Å,or from about 50-1250 Å, or from about 50-1000 Å, or from about 50-750Å.

The BET SSA, pore volume and average particle size may vary depending onthe amount of silicon in the silicon-carbon particulate. For example, athigh silicon levels, e.g., a weight ratio of Si:C of at least about 3:1,or at least about 4:1, or at least about 5:1, or at least about 6:1, orat least about 7:1, or at least about 8:1, the BET SSA and pore volumewill be higher, and the average particle size will be lower, compared toa silicon-carbon particulate in which the weight ratio of Si:C is atleast about 1:3, or at least about 1:4, or at least about 1:5, or atleast about 1:6, or at least about 1:7, or at least about 1:8.

Thus, in certain embodiments, such as Embodiment A, the silicon-carbonparticulate composite may be further characterized in having:

-   -   (1) a BET specific surface area (SSA) of from about 100 to about        400 m²/g, for example, from about 200-400 m²/g, or from about        250-350 m²/g, or from about 275-325 m²/g, or from about 275-300        m²/g, or from about 300-325 m²/g; and/or    -   (2) an average particle size of from about 50 Å to about 300 Å,        for example, from about 50-200 Å, or from about 50-150 Å, or        from about 50-100 Å, or from about 75-100 Å, or from about 80-95        Å.

In such embodiments, the BET SSA may be from about 275-325 m²/g, theaverage particle size may be from about 50-200 Å, for example, fromabout 50-150 Å, or from about 50-100 Å, the BJH average pore width maybe from about 100 Å to about 140 Å, the BJH volume of pores may be fromabout 0.75 cm³/g, to about 1.25 cm³/g, and the microporosity may be fromabout 5-20%, for example, from about 12-18% or from about 8-12%.

In certain embodiments, such as Embodiment B, the silicon-carbonparticulate composite may be further characterized in having:

-   -   (1) a BET specific surface area (SSA) of from about 10 m²/g to        about 100 m²/g, for example, from about 20-80 m²/g, or from        about 20-60 m²/g, or from about 30-50 m²/g, or from about 35-45        m²/g, or from about 40-45 m²/g; and/or    -   (2) an average particle size of from about 250 Å to about 1000        Å, for example, from about 450-850 Å, or from about 500-800 Å,        or from about 550-700 Å, or from about 575-675 Å, or from about        600-650 Å, or from about 620-640 Å.

In such embodiments, the BET SSA may be from about 30-50 m²/g, theaverage particle size may be from about 300-1000 Å, for example, fromabout 500-700 Å, or about 600-650 Å, the BJH average pore width may befrom about 130 Å to about 150 Å, the BJH volume of pores may be fromabout 0.12 cm³/g, to about 0.16 cm³/g, and the microporosity may be fromabout 8-15%, for example, from about 10-13%.

In certain embodiments, such as Embodiment A, a majority of thesilicon-carbon particulate composite is silicon, based on the totalweight of the composite, for example, at least about 60 wt. %, or atleast about 70 wt. %, or at least about 80 wt. %, or at least about 90wt. % of the composite is silicon.

In certain embodiments, such as Embodiment B, a majority of thesilicon-carbon particulate composite is carbon, based on the totalweight of the composite, for example, at least about 60 wt. %, or atleast about 70 wt. %, or at least about 80 wt. %, or at least about 90wt. % of the composite is carbon.

In certain embodiments, the silicon-carbon particulate composition has ananostructure which inhibits or prevents silicon pulverization when usedas active material in a negative electrode of a Li-ion battery.

By “inhibiting or preventing silicon pulverization” is meant that Li isde-intercalated in a single amorphous phase in a continuous process,more particularly, that the nanostructure promotes the formation ofamorphous Li_(x)Si with the gradual change of X in one continuous phase,and in the substantial absence of the formation of two phases containingcrystalline Si and crystalline Li₁₅S₄. The formation of crystallineLi₁₅S₄ is detectable in a 1^(st) cycle Li intercalation andde-intercalation curve by the presence of a characteristic plateau inthe de-intercalation curve part way between full charge and fulldischarge. The plateau is characterized in that the Potential vs.Li/Li+[V] (which is the Y-axis of the 1^(st) cycle Li intercalation andde-intercalation curve) changes by no more than about 0.05 V across aSpecific Charge/372 mAh/g (which is the X-axis of the 1^(st) cycle Liinteraction and de-intercalation curve) of 0.2. An example of thischaracteristic plateau is shown in FIG. 4C. Without wishing to be boundby theory, it is believed that the silicon-carbon particulate compositereduces the extent of volume expansion during lithium intercalation, bypreventing or at least inhibiting the formation of Si—Li crystallinealloy phases, and promotes the formation of an amorphous Li_(x)Si phase,and moreover provides sufficient pore void space to better accommodatesaid volume expansion during lithiation, thus improving cyclingstability and/or reducing capacity losses during cycling of the Li-ionbattery. The result is improvement in cycle stability and reduction inspecific charge loss.

Additionally or alternatively, therefore, in certain embodiments, thesilicon particulate has a nanostructure which maintains electrochemicalcapacity of a negative electrode, of a Li-ion battery when used asactive material. By “maintains electrochemical capacity”, means that thespecific charge of the negative electrode after 100 cycles is at least85% of the specific charge after 10 cycles, for example, at least 90% ofthe specific charge after 10 cycles, or at least 95% of the specificcharge after 10 cycles. In other words, the negative electrodecomprising the silicon particulate may have at least 85% capacityretention after 100 cycles, for example, at least 90% capacity retentionafter 100 cycles, or at least 95% capacity retention after 100 cycles.

In certain embodiments, the silicon-carbon particulate composite isprepared by co-milling silicon and carbon starting materials under wetconditions, i.e., by wet-milling, in accordance with the methodsdescribed herein.

Method of Making Silicon Particulate

The silicon-carbon particulate composite may be manufactured byco-milling silicon particulate and carbonaceous particulate startingmaterials under wet conditions to produce a silicon-carbon particulatecomposite according to the first aspect and/or having a nanostructurewhich inhibits or prevents silicon pulverization and/or maintainselectrochemical capacity when use as active material in a negativeelectrode of a Li-ion battery. By “wet conditions” or “wet-milling” ismeant milling in the presence of a liquid, which may be organic, aqueousor a combination thereof.

In certain embodiments, the silicon particulate starting materialcomprises silicon microparticles having particle sizes of from about 1μm to about 100 μm, for example, from about 1 μm to about 75 μm, or fromabout 1 μm to about 50 μm, or from about 1 μm to about 25 μm, or fromabout 1 μm to about 10 μm. In certain embodiments, the siliconparticulate starting material is a micronized silicon particulate havinga particle size of from about 1 μm to about 10 μm. Carbonaceousparticulate starting materials are described below.

In certain embodiments, the method comprises one or more of thefollowing:

-   -   (iv) wet-milling in the presence of a solvent, for example, an        aqueous alcohol-containing mixture,    -   (v) wet-milling in a rotor-stator mill, a colloidal mill or a        media mill,    -   (vi) wet-milling under conditions of high shear and/or high        power density,    -   (vii) wet-milling in the presence of relatively hard and dense        milling media, and    -   (viii) drying.

In certain embodiments, the method comprise two or more of (i), (ii),(iii) and (iv) followed by drying, for example, three or more of (i),(ii), (iii) and (iv) followed by drying, or all of (i), (ii), (iii) and(iv) followed by drying.

(i) Wet Milling in the Presence of an Aqueous Alcohol-Containing Mixture

In certain embodiments, the solvent is an aqueous alcohol-containingmixture may comprise water and alcohol in a weight ratio of from about10:1 to about 1:1, for example, from about 8:1 to about 2:1, or fromabout 6:1 to about 3:1, or from about 5:1 to about 4:1. The total amountof liquid may be such to produce a slurry of the silicon particulatestarting material having a solids content of no greater than about 30wt. %, for example, no greater than about 25 wt. %, or no greater thanabout 20 wt. %, or no greater than about 15 wt. %, or at least about 5wt. %, or at least about 10 wt. %.

The liquid plus silicon particulate starting material and carbonaceousparticulate starting material may be in the form of a slurry. In theseembodiments, the alcohol could be replaced with an organic solvent otherthan an alcohol, or a mixture of organic solvents comprising alcohol andanother organic solvents, or a mixture of organic solvents other thanalcohol, with the weight ratios given above pertaining to the totalamount of organic solvent.

The alcohol may be a low molecular weight alcohol having up to about 4carbon atoms, for example, methanol, ethanol, propanol or butanol. Incertain embodiments, the alcohol is propanol, for example, isopropanol.

(ii) And (iii)

In certain embodiments, the wet-milling is conducted in a rotor statormill, a colloidal mill or a media mill. These mills are similar in thatthey can be used to generate high shear conditions and/or high powerdensities.

A rotor-stator mill comprises a rotating shaft (rotor) and an axiallyfixed concentric stator. Toothed varieties have one or more rows ofintermeshing teeth on both the rotor and the stator with a small gapbetween the rotor and stator, which may be varied. The differentialspeed between the rotor and the stator imparts extremely high shear.Particle size is reduced by both the high shear in the annular regionand by particle-particle collisions and/or particle-media collisions, ifmedia is present.

A colloidal mill is another form of rotor-stator mill. It is composed ofa conical rotor rotating in a conical stator. The surface of the rotorand stator can be smooth, rough or slotted. The spacing between therotor and stator is adjustable by varying the axial location of therotor to the stator. Varying the gap varies not only the shear impartedto the particles but also the mill residence time and the power densityapplied. Particle size reduction may be affected by adjusting the gapand the rotation rate, optionally in the presence of media.

Media mills are different in operation than a rotor-stator mill butlikewise can be used to generate high shear conditions and powerdensities. The media mill may be a pearl mill or bead mill or sand mill.The mill comprises a milling chamber and milling shaft. The millingshaft typically extends the length of the chamber. The shaft may haveeither radial protrusions or pins extending into the milling chamber, aseries of disks located along the length of the chamber, or a relativelythin annular gap between the shaft mill chamber. The typically sphericalchamber is filled with the milling media. Media is retained in the millby a mesh screen located at the exit of the mill. The rotation of theshaft causes the protrusions to move milling media, creating conditionsof high shear and power density. The high energy and shear that resultfrom the movement of the milling media is imparted to the particles asthe material is circulated through the milling chamber.

The rotation speed within the mill may be at least about 5 m/s, forexample, at least about 7 m/s or at least about 10 m/s. The maximumrotation speed may vary from mill to mill, but typically is no greaterthan about 20 m/s, for example, no greater than about 15 m/s.Alternatively, the speed may be characterized in terms of rpm. Incertain embodiments, the rpm of the rotor-stator or milling shaft in thecase of a media mill may be at least about 5000 rpm, for example, atleast about 7500 rpm, or at least about 10,000 rpm, or at least about11,000 rpm. Again, maximum rpm may be vary from mill to mill, buttypically is no greater than about 15,000 rpm. Power density may be atleast about 2 kW/l (I=litre of slurry), for example, at least about 2.5kW/l, or at least about 3 kW/l. In certain embodiments, the powerdensity is no greater than about 5 kW/l, for example, no greater thanabout 4 kW/l.

In certain embodiments, the rpm of the rotor-stator or milling shaft inthe case of a media mill may be at least about 500 rpm, for example, atleast about 750 rpm, or at least about 1000 rpm, or at least about 1500rpm. Again, maximum rpm may be vary from mill to mill, but typically isno greater than about 3000 rpm.

Residence in time within the mill is less than 24 hours, for example,equal to or less than about 18 hours, or equal to or less than about 12hours, or equal to or less than about 6 hours, or equal to or less thanabout 4 hours, or equal to or less than about 220 minutes, or equal toor less than about 200 minutes, or equal to or less than about 180minutes, or equal to or less than about 160 minutes, or equal to or lessthan about 140 minutes, or equal to or less than about 120 minutes, orequal to or less than about 100 minutes, or equal to or less than about80 minutes, or equal to or less than about 60 minutes, or equal to orless than about 40 minutes, or equal to or less than about 20 minutes.

(iv) Wet-Milling in the Presence of Relatively Hard and Dense MillingMedia

In certain embodiments, the milling media is characterized by having adensity of at least about 3 g/cm³, for example, at least about 3.5g/cm³, or at least about 4.0 g/cm³, or at least about 4.5 g/cm³, or atleast about 5.0 g/cm³, or at least about 5.5 g/cm³, or at least about6.0 g/cm³. In certain embodiments, the milling media is a ceramicmilling media, for example, yttria-stabilized zirconia, ceria-stabilizedzirconia, fused zirconia, alumina, alumina-silica, alumina-zirconia,alumina-silica-zironia, and ytrria or ceria stabilized forms thereof.The milling media, for example, ceramic milling media, may be in theform of beads. The milling media, for example, ceramic milling media mayhave a size of less than about 10 mm, for example, equal to or less thanabout 8 mm, or equal to or less than about 6 mm, or equal to or lessthan about 4 mm, or equal to or less than about 2 mm, or equal to orless than about 1 mm, or equal to or less than about 0.8 mm, or equal orless than about 0.6 mm, or equal to or less than about 0.5 mm. Incertain embodiments, the milling media has a size of at least 0.05 mm,mm, for example, at least about 0.1 mm, or at least about 0.2 mm, or atleast about 0.3 mm, or at least about 0.4 mm.

In certain embodiments, wet milling is conducted in a planetary ballmill with milling media, for example, ceramic milling media, having asize of up to about 10 mm.

(v) Drying

Drying may be affected by any suitable technique using any suitabledrying equipment. Typically, the first step of the drying (or,alternatively, the last action of the milling step) is recovering thesolid material from the dispersion, for example by filtration orcentrifugation, which removes the bulk of the liquid before the actualdrying takes place. In some embodiments, the drying step c) is carriedout by a drying technique selected from subjecting to hot air/gas in anoven or furnace, spray drying, flash or fluid bed drying, fluidized beddrying and vacuum drying.

For example, the dispersion may be directly, or optionally afterfiltering the dispersion through a suitable filter (e.g. a <100 μmmetallic or quartz filter), introduced into an air oven at typically 120to 230° C., and maintained under these conditions, or the drying may becarried out at 350° C., e.g., for 3 hours. In cases where a surfactantis present, the material may optionally be dried at higher temperaturesto remove/destroy the surfactant, for example at 575° C. in a mufflefurnace for 3 hours.

Alternatively, drying may also be accomplished by vacuum drying, wherethe processed dispersion is directly, or optionally after filtering thedispersion through a suitable filter (e.g. a <100 μm metallic or quartzfilter), introduced, continuously or batch-wise, into a closed vacuumdrying oven. In the vacuum drying oven, the solvent is evaporated bycreating a high vacuum at temperatures of typically below 100° C.,optionally using different agitators to move the particulate material.The dried powder is collected directly from the drying chamber afterbreaking the vacuum.

Drying may for example also be achieved with a spray dryer, where theprocessed dispersion is introduced, continuously or batch wise, into aspray dryer that rapidly pulverizes the dispersion using a small nozzleinto small droplets using a hot gas stream. The dried powder istypically collected in a cyclone or a filter. Exemplary inlet gastemperatures range from 150 to 350° C., while the outlet temperature istypically in the range of 60 to 120° C.

Drying can also be accomplished by flash or fluid bed drying, where theprocessed expanded graphite dispersion is introduced, continuously orbatch wise, into a flash dryer that rapidly disperses the wet material,using different rotors, into small particles which are subsequentlydried by using a hot gas stream. The dried powder is typically collectedin a cyclone or a filter. Exemplary inlet gas temperatures range from150 to 300° C. while the outlet temperature is typically in the range of100 to 150° C.

Alternatively, the processed dispersion may be introduced, continuouslyor batch-wise, into a fluidized bed reactor/dryer that rapidly atomizesthe dispersion by combining the injection of hot air and the movement ofsmall media beads. The dried powder is typically collected in a cycloneor a filter. Exemplary inlet gas temperatures range from 150 to 300° C.while the outlet temperature is typically in the range of 100 to 150° C.

Drying can also be accomplished by freeze drying, where the processeddispersion is introduced, continuously or batch wise, into a closedfreeze dryer where the combination of freezing the solvent (typicallywater or water/alcohol mixtures) and applying a high vacuum sublimatesthe frozen solvent. The dried material is collected after all solventhas been removed and after the vacuum has been released.

The drying step may optionally be carried out multiple times. If carriedout multiple times, different combinations of drying techniques may beemployed. Multiple drying steps may for example be carried out bysubjecting the material to hot air (or a flow of an inert gas such asnitrogen or argon) in an oven/furnace, by spray drying, flash or fluidbed drying, fluidized bed drying, vacuum drying or any combinationthereof.

In some embodiments, the drying step is conducted at least twice,preferably wherein the drying step comprises at least two differentdrying techniques selected from the group consisting of subjecting tohot air in an oven/furnace, spray drying, flash or fluid bed drying,fluidized bed drying and vacuum drying.

In certain embodiments, drying is accomplished in an oven, for example,in air at a temperature of at least about 100° C., for example, at leastabout 105° C., or at least about 110° C. In other embodiments, drying isdone by spray drying, for example, at a temperature of at least about50° C., or at least about 60° C., or at least about 70° C.

In certain embodiments, the carbonaceous particulate startingmaterial(s) is selected from natural graphite, synthetic graphite, coke,exfoliated graphite, graphene, few-layer graphene, graphite fibers,nano-graphite, non-graphitic carbon, carbon black, petroleum- or coalbased coke, glass carbon, carbon nanotubes, fullerenes, carbon fibers,hard carbon, graphitized fined coke, or mixtures thereof. Specificcarbonaceous particulate materials include, but are not limited toexfoliated graphites as described in WO 2010/089326 (highly orientedgrain aggregate graphite, or HOGA graphite), or as described inco-pending EP application no. 16 188 344.2 (wet-milled and driedcarbonaceous sheared nano-leaves) filed on Sep. 12, 2016.

In certain embodiments, the carbonaceous particulate starting materialis graphite, for example, natural or synthetic graphite, exfoliatedgraphite, or an expanded graphite, or combinations thereof, for example,a combination of expanded graphite and a synthetic graphite. In certainembodiments, the synthetic graphite is surface-modified, for example,coated, for example, with an amorphous coating. In certain embodiments,the synthetic graphite is not surface-modified.

The carbonaceous particulate starting material or materials may beselected such that following co-milling they provide a carbon matrixhaving a BET SSA which is suitable for use negative electrode of aLi-ion battery.

In certain embodiments, the silicon particulate starting material isinitially milled in the absence of carbonaceous particulate startingmaterial, for example, for a period of up to about 1 hour, up to about45 mins, or up to about 30 mins, or up to about 15 mins, and thencombined with carbonaceous particulate starting material and co-milledfor a further period.

In certain embodiments, the carbonaceous particulate starting is addedgradually or in batches during the co-milling process. In certainembodiments, the silicon particulate starting materials is addedgradually or in batches during the co-milling process.

In other embodiments, the carbonaceous particulate starting material isinitially milled in the absence of silicon particulate startingmaterial, and then combined with silicon particulate starting materialand co-milled for a further period.

Precursor Compositions

The silicon-carbon particulate composite may be used as active materialin a negative electrode with or without additional carbonaceousparticulate material and or Si-active material.

Sources of additional carbonaceous particulate materials are may andvarious and may be selected from selected from natural graphite,synthetic graphite, coke, exfoliated graphite, graphene, few-layergraphene, graphite fibers, nano-graphite, non-graphitic carbon, carbonblack, petroleum- or coal based coke, glass carbon, carbon nanotubes,fullerenes, carbon fibers, hard carbon, graphitized fined coke, ormixtures thereof. Specific carbonaceous particulate materials include,but are not limited to exfoliated graphites as described in WO2010/089326 (highly oriented grain aggregate graphite, or HOGAgraphite), or as described in co-pending EP application no. 16 188 344.2(wet-milled and dried carbonaceous sheared nano-leaves) filed on Sep.12, 2016.

In certain embodiments, the additional carbonaceous particulate materialis carbon black, for example conductive carbon black. In certainembodiments, the carbon black has a BET SSA of less than about 100 m²/g,for example, from about 30 m²/g to about 80 m²/g, or from about 30 m²/gto about 60 m²/g, or from about 35 m²/g to about 55 m²/g, or from about40 m²/g to about 50 m²/g. In other embodiments, the carbon black, whenpresent, may have a BET SSA of less than about 1200 m²/g, for example,lower than about 1000 m²/g or lower than about 800 m²/g, or lower thanabout 600 m²/g, or lower than about 400 m²/g, or lower than about 200m²/g.

In certain embodiments, the additional carbonaceous particulate materialcomprises at least two different types of carbonaceous particulatematerial, for example, at least three different types of carbonaceousparticulate material. The additional carbonaceous particulate serves asa carbon matrix for the silicon-carbon particulate composite

The carbon matrix may have a BET SSA of less than about 100 m²/g, forexample, less than about 50 m²/g, or less than about 25 m²/g, or lessthan about 20 m²/g, or less than about 15 m²/g, or less than about 10m²/g, or less than about 8.0 m²/g, or less than about 6.0 m²/g, or lessthan about 4.0 m²/g. In certain embodiments, the carbon matrix has a BETSSA of at least about 1.0 m²/g, or at least about 2.0 m²/g, or at leastabout 3.0 m²/g.

In certain embodiments, the additional carbonaceous particulate materialis or comprises a synthetic graphite, for example, a surface-modifiedsynthetic graphite. In certain embodiments, the surface-modifiedsynthetic graphite comprises core particles with a hydrophilicnon-graphitic carbon coating, having a BET SSA of less than about 49m²/g, for example, less than about 25 m²/g, or less than about 10 m²/g.In such embodiments, the core particles are synthetic graphiteparticles, or a mixture of synthetic graphite particles and siliconparticles. Such a material and the preparation thereof is described inWO-A-2016008951, the entire contents of which are incorporated herein byreference. In certain embodiments, the at least one carbonaceousparticulate is a surface modified carbonaceous particulate materialaccording to any one of claims 1-10 of WO-A-2016008951 as published on21 Jan. 2016, or that made by or obtainable by a process according toany one of claims 11-17 of WO-A-2016008951 as published on 21 Jan. 2016.

In certain embodiments, the additional carbonaceous particulate materialis or comprises a surface-modified synthetic graphite, for examplesynthetic graphite which has been surface modified by either chemicalvapor deposition (“CVD coating”) or by controlled oxidation at elevatedtemperatures. In certain embodiments, the synthetic graphite prior tosurface-modification is characterized by characterized by a BET SSA offrom about 1.0 to about 4.0 m²/g, and by exhibiting a ratio of theperpendicular axis crystallite size L_(c) (measured by XRD) to theparallel axis crystallite size L_(a) (measured by Raman spectroscopy),i.e. L_(c)/L_(a) of greater than 1. Following surface-modification, thesynthetic is characterized by an increase of the ratio between thecrystallite size L_(c) and the crystallite size L_(a). In other words,the surface-modification process lowers the crystallite size L_(a)without substantially affecting the crystallite size L_(c). In oneembodiment, the surface-modification of the synthetic graphite isachieved by contacting the untreated synthetic graphite with oxygen atelevated temperatures for a sufficient time to achieve an increase ofthe ratio L_(c)/L_(a), preferably to a ratio of >1, or even greater,such as >1.5, 2.0, 2.5 or even 3.0. Moreover, the process parameterssuch as temperature, amount of oxygen-containing process gas andtreatment time are chosen to keep the burn-off rate relatively low, forexample, below about 10%, below 9% or below 8%. The process parametersare selected so as to produce a surface-modified synthetic graphitemaintaining a BET surface area of below about 4.0 m²/g.

The process for modifying the surface of synthetic graphite may involvea controlled oxidation of the graphite particles at elevatedtemperatures, such as ranging from about 500 to about 1100° C. Theoxidation is achieved by contacting the synthetic graphite particleswith an oxygen-containing process gas for a relatively short time in asuitable furnace such as a rotary furnace. The process gas containingthe oxygen may be selected from pure oxygen, (synthetic or natural) air,or other oxygen-containing gases such as CO2, CO, H2O (steam), O3, andNOx. It will be understood that the process gas can also be anycombination of the aforementioned oxygen-containing gases, optionally ina mixture with an inert carrier gas such as nitrogen or argon. It willgenerally be appreciated that the oxidation process runs faster withincreased oxygen concentration, i.e., a higher partial pressure ofoxygen in the process gas. The process parameters such as treatment time(i.e. residence time in the furnace), oxygen content and flow rate ofthe process gas as well as treatment temperature are chosen to keep theburn off rate below about 10% by weight, although it is in someembodiments desirable to keep the burn-off rate even lower, such asbelow 9%, 8%, 7%, 6% or 5%. The burn-off rate is a commonly usedparameter, particularly in the context of surface oxidation treatments,since it gives an indication on how much of the carbonaceous material isconverted to carbon dioxide thereby reducing the weight of the remainingsurface-treated material.

The treatment times during which the graphite particles are in contactwith the oxygen-containing process gas (e.g. synthetic air) may berelatively short, thus in the range of 2 to 30 minutes. In manyinstances the time period may be even shorter such as 2 to 15 minutes, 4to 10 minutes or 5 to 8 minutes. Of course, employing different startingmaterials, temperatures and oxygen partial pressure may require anadaptation of the treatment time in order to arrive at asurface-modified synthetic graphite having the desired structuralparameters as defined herein. Oxidation may be achieved by contactingthe synthetic graphite with air or another oxygen containing gas at aflow rate generally ranging from 1 to 200 l/min, for example, from 1 to50 l/min, or from 2 to 5 l/min. The skilled person will be able to adaptthe flow rate depending on the identity of the process gas, thetreatment temperature and the residence time in the furnace in order toarrive at a surface-modified graphite.

Alternatively, the synthetic graphite starting material is subjected toa CVD coating treatment with hydrocarbon-containing process gas atelevated temperatures for a sufficient time to achieve an increase ofthe ratio L_(c)/L_(a), preferably to a ratio of >1, or even greater,such as >1.5, 2.0, 2.5 or even 3.0. Suitable process andsurface-modified synthetic graphite materials are described in U.S. Pat.No. 7,115,221, the entire contents of which are hereby incorporated byreference. The CVD process coats the surface of graphite particles withmostly disordered (i.e., amorphous) carbon-containing particles. CVDcoating involves contacting the synthetic graphite starting materialwith a process gas containing hydrocarbons or a lower alcohol for acertain 30 time period at elevated temperatures (e.g. 500° to 1000° C.).The treatment time will in most embodiments vary from 2 to 120 minutes,although in many instances the time during which the graphite particlesare in contact with the process gas will only range from 5 to 90minutes, from 10 to 60 minutes, or from 15 to 30 minutes. Suitable gasflow rates can be determined by those of skill in the art. In someembodiments, the process gas contains 2 to 10% of acetylene or propanein a nitrogen carrier gas, and a flow rate of around 1 m³/h.

In certain embodiments, the additional carbonaceous particulate is orcomprises (e.g., in admixture with another carbonaceous particulatematerial) a synthetic graphite which has not been surface-modified,i.e., a non-surface-modified synthetic graphite. In addition to the BETSSA, particle size distribution and spring back described above, thenon-surface modified synthetic particulate may have on or more of thefollowing properties:

an interlayer spacing c/2 (as measured by XRD) of equal to or less thanabout 0.337 nm, for example, equal to or less than about 0.336;

a crystallite size L_(c) (as measured by XRD) of from 100 nm to about150 nm, for example, from about 120 nm to about 135 nm;

a xylene density of from about 2.23 to about 2.25 g/cm³, for example,from about 0.235 to about 0.245 g/cm³;

a Scott density of from about 0.15 g/cm³ to about 0.60 g/cm³, forexample, from about 0.30 to about 0.45 g/cm³.

In certain embodiments, the non-surface-modified synthetic graphite isprepared according to the methods described in WO-A-2010/049428, theentire contents of which are hereby incorporated by reference.

In certain embodiments, the additional carbonaceous particulate has aBET SSA higher than about 8 m²/g and lower than about 20 m²/g, forexample, lower than about 15 m²/g, or lower than about 12 m²/g, or lowerthan about 10 m²/g. In such embodiments, carbonaceous particulatematerials, may have a spring back of less than 20%, for example, lessthan about 18%, or less than about 16%, or less than about 14%, or equalto or less than about 12%, or equal to or less than about 10%. In suchembodiments, the carbonaceous particulate material may have a particlesize distribution as follows:

a d₉₀ of at least about 8 μm, for example, at least about 10 μm, or atleast about 12 μm, optionally less than about 25 μm, or less than about20 μm; and/or

a d₅₀ of from about 5 μm to about 12 μm, for example, from about 5 μm toabout 10 μm, or from about 7 μm to about 9 μm; and/or

a d₁₀ of from about 1 μm to about 5 μm, for example, from about 2 μm toabout 5 μm, or from about 3 μm to about 5 μm, or from about 3 μm μm toabout 4 μm.

In certain embodiments, the additional carbonaceous particulate materialhas a BET SSA higher than about 20 m²/g, for example, higher than about25 m²/g, or higher than about 30 m²/g, optionally lower than about 40m²/g, for example, lower than about 35 m²/g. In such embodiments, thesecond carbonaceous particulate material may have a spring back of lessthan 20%, for example, less than about 18%, or less than about 16%, orless than about 14%, or equal to or less than about 12%, or equal to orless than about 10%. In such embodiments, the carbonaceous particulatematerial may be graphite, for example, natural or synthetic graphite,for example, an exfoliated graphite (e.g. as described in WO 2010/089326or EP application no. 16 188 344.2 (wet-milled and dried carbonaceoussheared nano-leaves) filed on Sep. 12, 2016, or expanded graphite. Insuch embodiments, the additional carbonaceous particulate material mayhave a particle size distribution as follows:

a d₉₀ of at least about 4 μm, for example, at least about 6 μm, or atleast about 8 μm, optionally less than about 15 μm, or less than about12 μm; and/or

a d₅₀ of from about 2 μm to about 10 μm, for example, from about 5 μm toabout 10 μm, or from about 6 μm to about 9 μm; and/or

a d₁₀ of from about 0.5 μm to about 5 μm, for example, from about 1 μmto about 4 μm, or from about 1 μm to about 3 μm, or from about 1.5 μm μmto about 2.5 μm.

Based on the total weight of the precursor composition, the additionalcarbonaceous particulate material may be present in an amount of fromabout 1 wt. % to about 90 wt. %, for example, from about 5 wt. % toabout 50 wt. %, or from about 5 wt. % to about 25 wt. %, or from about 5wt. % to about 15 wt. %, or less than about 10 wt. %, or less than about5 wt. %.

In certain embodiments, any of the additional carbonaceous materialsdescribed herein may be used individually in the precursor compositionalong with the silicon-carbon particulate composite, or as a mixture ofdifferent additional carbonaceous materials. Combinations not explicitlydescribed are contemplated

In certain embodiments, the precursor composition comprises from about0.1 wt. % to about 90 wt. % of silicon, based on the total weight of theprecursor composition, for example, from about 0.1 wt. % to about 80 wt.%, or from about 0.1 wt. % to about 70 wt. %, or from about 0.1 wt. % toabout 60 wt. %, or from about 0.1 wt. % to about 50 wt. %, or from about0.1 wt. % to about 40 wt. %, or from about 0.5 wt. % to about 30 wt. %,or from about 1 wt. % to about 25 wt. %, or from about 1 wt. % to about20 wt. %, or from about 1 wt. % to about 15 wt. %, or from about 1 wt.to about 10 wt. %, or from about 1 wt. % to about 5 wt. %. The amount ofsilicon-carbon particulate composite may be varied according in order toproduce a precursor composition having the required amount of silicon.

In certain embodiments, the precursor composition comprises from about 1wt. % to about 90 wt. % of silicon, based on the total weight of thenegative electrode, for example, from about 0.1 wt. % to about 80 wt. %,or from about 0.1 wt. % to about 70 wt. %, or from about 0.1 wt. % toabout 60 wt. %, or from about 0.1 wt. % to about 50 wt. %, or from about0.1 wt. % to about 40 wt. %, or from about 2 wt. % to about 30 wt. %, orfrom about 5 wt. % to about 25 wt. %, or from about 7.5 wt. % to about20 wt. %, or from about 10 wt. to about 17.5 wt. %, or from about 12.5wt. % to about 15 wt. %. Again, the amount of silicon-carbon particulatecomposite may be varied according in order to produce a precursorcomposition or negative electrode having the required amount of silicon.

The precursor composition may be made by mixing the additionalcarbonaceous particulates in suitable amounts forming the carbon matrixoptionally together with the silicon-carbon particulate composite. Incertain embodiments, the carbon matrix is prepared, and then thesilicon-carbon particulate composite is combined with the carbon matrix,again, using any suitable mixing technique. In certain embodiments, thecarbon matrix is prepared at a first location and then combined with thesilicon-carbon particulate composite in a second location. In certainembodiments, a carbon matrix is prepared in a first location and thentransported to a second location (e.g., an electrode manufacturing site)where it is combined with silicon-carbon particulate composite andoptionally additional carbonaceous particulate if desired, and then withany additional components to manufacture a negative electrode therefrom,as described below.

In certain embodiments, the method of preparing a precursor compositionfor a negative electrode of a Li-ion battery, comprises, preparing,obtaining, providing or supplying a carbonaceous particulate andcombining with a silicon-carbon particulate composite as describedherein.

In certain embodiments, the method of preparing a precursor compositionfor a negative electrode of a Li-ion battery, comprises combining asilicon-carbon particulate composite according to any one of claims 1-5or obtainable by a method according to any one of claims 13-19 with afurther carbonaceous particulate.

In certain embodiments, the further carbonaceous particulate is preparedat a first location and combined with the silicon-carbon particulatecomposite at a second location.

In certain embodiments, the further or additional carbonaceousparticulate and silicon-carbon particulate composite are prepared andcombined at the same location.

Negative Electrode for a Li-Ion Battery

The silicon-carbon particulate composites and precursor compositions asdefined herein can be used for manufacturing negative electrodes forLi-ion batteries, in particular Li-ion batteries empowering electricvehicles, or hybrid electric vehicles, or energy storage units.

Thus, another aspect is a negative electrode comprising a silicon-carbonparticulate composite as described herein.

Another aspect is a negative electrode comprising or made from aprecursor composition as described herein.

In certain embodiments, the negative electrode comprises a sufficientamount of the silicon-carbon particulate composite such that thenegative electrode comprises at least 1 wt. % of silicon, based on thetotal weight of the electrode, for example, at least about 2 wt. %, orat least about 5 wt. %, or at least about 10 wt. %, and optionally up toabout 90 wt. % of silicon, based on the total weight of the electrode,for example, up to about 80 wt. %, or up to about 70 wt. %, or up toabout 60 wt. %, or up to about 50 wt. %, or up to about 40 wt. %. Incertain embodiments, the negative electrode comprises from about 5 wt. %to about 35 wt. silicon, based on the total weight of the electrode, forexample, from about 5 wt. % to about 30 wt. %, or from about 5 wt. % toabout 25 wt. %, or from about 10 wt. % to about 20 wt. %, or from about10 wt. % to about 18 wt. %, or from about 12 wt. % to about 16 wt. %, orfrom about 13 wt. % to about 15 wt. % silicon.

The negative electrode may be manufactured using conventional methods.In certain embodiments, the precursor composition is combined with asuitable binder. Suitable binder materials are many and various andinclude, for example, cellulose, acrylic or styrene-butadiene basedbinder materials such as, for example, carboxymethyl cellulose and/orPAA (polyacrylic acid) and/or styrene-butadiene rubber. The amount ofbinder may vary. The amount of binder may be from about 1 wt. to about20 wt. %, based on the total weight of the negative electrode, forexample, from about 1 wt. % to about 15 wt. %, or from about 5 wt. % toabout 10 wt. %, or from about 1 wt. % to about 5 wt. %, or from about 2wt. % to about 5 wt. %, or from about 3 wt. % to about 5 wt. %.

In certain embodiments, a method of manufacturing a negative electrodefor a Li-ion battery, comprises forming the negative electrode from aprecursor composition as described herein or obtainable by a method asdescribed herein, optionally wherein the precursor composition comprisesadditional components or is combined with additional components duringforming, optionally wherein the additional components include binder, asdescribed in the preceding paragraph. The negative electrode may then beused in a Li-ion battery.

In certain aspects, therefore, there is provided a Li-ion batterycomprising a negative electrode which comprises a silicon-carbonparticulate composite, wherein silicon pulverization does not occurduring 1^(st) cycle lithium intercalation and de-intercalation, and/orelectrochemical capacity is maintained after 100 cycles. In certainembodiments, the Li-ion battery comprises silicon-carbon particulatecomposite as defined herein, optionally further comprising additionalcarbonaceous particulate material as described herein

As described above, the Li-ion battery may be incorporated in a devicerequiring power. In certain embodiments, the device is an electricvehicle, for example, a hybrid electric vehicle or a plug-in electricvehicle.

In certain embodiments, the precursor composition is incorporated in anenergy storage device.

In certain embodiments, the silicon particulate and/or precursorcomposition is incorporated in an energy storage and conversion system,for example, an energy storage and conversion system which is orcomprises a capacitor, or a fuel cell.

In other embodiments, the carbon matrix is incorporated in a carbonbrush or friction pad.

In other embodiments, the precursor composition is incorporated within apolymer composite material, for example, in an amount ranging from about5-95 wt. %, or 10-85%, based on the total weight of the polymercomposite material.

Uses

In related aspects and embodiments, there is provided the use of asilicon-carbon particulate composite as active material in a negativeelectrode of a Li-ion battery to inhibit or prevent siliconpulverization during cycling, for example, during 1^(st) cycle Liintercalation and de-intercalation, and/or to maintain electrochemicalcapacity after 100 cycles. In certain embodiments, the silicon-carbonparticulate composite is a silicon particulate according to the firstaspect. In certain embodiments, Li is electrochemically extracted froman amorphous lithium silicon phase and in the substantial absence of twocrystalline phases containing crystalline silicon metal and crystallineLi₁₅Si₄ alloy.

In another embodiments, the silicon-carbon particulate composite of thefirst aspect is used as active material in a negative electrode of aLi-ion battery for improving cycling stability of the Li-ion batterycompared to a Li-ion battery which comprises an active material which isa mixture of silicon particulate and carbonaceous particulate which isnot a composite and/or is not produced by co-milling under wetconditions and/or does not have a nanostructure which inhibits orprevents silicon pulverization during cycling, for example, during1^(st) cycle Li intercalation and/or does not have a nanostructure whichmaintains electrochemical capacity after 100 cycles.

Measurement Methods BET Specific Surface Area (BET SSA)

The method is based on the registration of the absorption isotherm ofliquid nitrogen in the range p/p₀=0.04-0.26, at 77 K. Following theprocedure proposed by Brunauer, Emmet and Teller (Adsorption of Gases inMultimolecular Layers, J. Am. Chem. Soc., 1938, 60, 309-319), themonolayer adsorption capacity can be determined. On the basis of thecross-sectional area of the nitrogen molecule, the monolayer capacityand the weight of the sample, the specific surface area can then becalculated. Meso- and macro-porosity parameters, including average porewidth and total volume of pores, were derived from the nitrogenadsorption data using the Barrett-Joyner-Halenda (BJH) theory andmicroporosity in relation to the total BET surface area was determinedusing the t-plot method. The average particle size was calculated fromthe BET surface area assuming nonporous spherical particles and thetheoretical density of the carbon/silicon composite.

X-Ray Diffraction

XRD data were collected using a PANalytical X'Pert PRO diffractometercoupled with a PANalytical X'Celerator detector. The diffractometer hasthe following characteristics shown in Table 1:

TABLE 1 Instrument data and measurement parameters InstrumentPANalytical X′Pert PRO X-ray detector PANalytical X′Celerator X-raysource Cu—K_(α) Generator parameters 45 kV-40 mA Scan speed 0.07°/s (forL_(c) and c/2) 0.01°/s (for [004]/[110] ratio) Divergence slit 1° (forL_(c) and c/2) 2° (for [004]/[110] ratio) Sample spinning 60 rpm

The data were analyzed using the PANalytical X'Pert HighScore Plussoftware.

Interlayer Spacing c/2

The interlayer space c/2 is determined by X-ray diffractometry. Theangular position of the peak maximum of the [002] reflection profilesare determined and, by applying the Bragg equation, the interlayerspacing is calculated (Klug and Alexander, X-ray Diffraction Procedures,John Wiley & Sons Inc., New York, London (1967)). To avoid problems dueto the low absorption coefficient of carbon, the instrument alignmentand non-planarity of the sample, an internal standard, silicon powder,is added to the sample and the graphite peak position is recalculated onthe basis of the position of the silicon peak. The graphite/siliconsample is mixed with the silicon standard powder by adding a mixture ofpolyglycol and ethanol. The obtained slurry is subsequently applied on aglass plate by means of a blade with 150 μm spacing and dried.

Crystallite Size L_(c)

Crystallite size L_(c) is determined by analysis of the [002] X-raydiffraction profiles and determining the widths of the peak profiles atthe half maximum. The broadening of the peak should be affected bycrystallite size as proposed by Scherrer (P. Scherrer, GottingerNachrichten 1918, 2, 98). However, the broadening is also affected byother factors such X-ray absorption, Lorentz polarization and the atomicscattering factor. Several methods have been proposed to take intoaccount these effects by using an internal silicon standard and applyinga correction function to the Scherrer equation. For the presentdisclosure, the method suggested by Iwashita (N. Iwashita, C. Rae Park,H. Fujimoto, M. Shiraishi and M. Inagaki, Carbon 2004, 42, 701-714) wasused. The sample preparation was the same as for the c/2 determinationdescribed above.

Crystallite Size L_(a)

Crystallite size L_(a) is calculated from Raman measurements usingequation:

L _(a)[Angstrom (

)]=C×(I _(G) /I _(D))

where constant C has values 44[

] and 58[

] for lasers with wavelength of 514.5 nm and 632.8 nm, respectively.

Xylene Density

The analysis is based on the principle of liquid exclusion as defined inDIN 51 901. Approx. 2.5 g (accuracy 0.1 mg) of powder is weighed in a 25ml pycnometer. Xylene is added under vacuum (20 mbar). After a few hoursdwell time under normal pressure, the pycnometer is conditioned andweighed. The density represents the ratio of mass and volume. The massis given by the weight of the sample and the volume is calculated fromthe difference in weight of the xylene filled pycnometer with andwithout sample powder.

Reference: DIN 51 901 Scott Density (Apparent Density)

The Scott density is determined by passing the dry powder through theScott volumeter according to ASTM B 329-98 (2003). The powder iscollected in a 1 in 3 vessel (corresponding to 16.39 cm³) and weighed to0.1 mg accuracy. The ratio of weight and volume corresponds to the Scottdensity. It is necessary to measure three times and calculate theaverage value. The bulk density is calculated from the weight of a 250mL sample in a calibrated glass cylinder.

Reference: ASTM B 329-98 (2003) Spring-Back

Spring-back is a source of information regarding the resilience ofcompacted graphite/silicon powders. A defined amount of powder is pouredinto a die. After inserting the punch and sealing the die, air isevacuated from the die. A compression force of 0.5 tons/cm² is appliedand the powder height is recorded. This height is recorded again afterthe pressure has been released. Spring-back is the height difference inpercent relative to the height under pressure.

Particle Size Distribution by Laser Diffraction (Wet PSD)

The presence of particles within a coherent light beam causesdiffraction. The dimensions of the diffraction pattern are correlatedwith the particle size. A parallel beam from a low-power laser lights upa cell which contains the sample suspended in water. The beam leavingthe cell is focused by an optical system. The distribution of the lightenergy in the focal plane of the system is then analyzed. The electricalsignals provided by the optical detectors are transformed into particlesize distribution by means of a calculator. A small sample ofsilicon/carbon dispersion or dried silicon/carbon is mixed with a fewdrops of wetting agent and a small amount of water. The sample isprepared in the described manner and measured after being introduced inthe storage vessel of the apparatus filled with water that usesultrasonic waves for improving dispersion.

References: —ISO 13320-1/—ISO 14887 Particle Size Distribution by LaserDiffraction (Dry PSD)

The Particle Size Distribution is measured using a Sympatec HELOS BRLaser diffraction instrument equipped with RODOS/L dry dispersion unitand VIBRI/L dosing system. A small sample is placed on the dosing systemand transported using 3 bars of compressed air through the light beam.The particle size distribution is calculated and reported in μm for thethree quantiles: 10%, 50% and 90%.

References: ISO 13320-1 Lithium-Ion Negative Electrode Half Cell Test

This test was used to quantify the specific charge ofnano-Si/carbon-based electrodes.

General half-cell parameters: 2 electrode coin cell design with Li metalfoil as counter/reference electrode, cell assembly in an argon filledglove box (oxygen and water content <1 ppm).Diameter of electrodes: 13 mm. A calibrated spring (100 N) was used inorder to have a defined force on the electrode. Tests were carried outat 25° C.Electrode loading on copper electrode: 6 mg/cm². Electrode density: 1.3g/cm³.Drying procedure: Coated Cu foils were dried for 1 h at 80° C., followedby 12 h at 150° C. under vacuum (<50 mbar). After cutting, theelectrodes were dried for 10 h at 120° C. under vacuum (<50 mbar) beforeinsertion into the glove box.Electrolyte: Ethylenecarbonate (EC):Ethylmethylcarbonate (EMC) 1:3(v/v), 1 M LiPF₆, 2% fluoroethylene carbonate, 0.5% vinylene carbonate.Separator: Glass fiber sheet, ca. 1 mm.Cycling program using a potentiostat/galvanostat: 1^(st) charge:constant current step 20 mA/g to a potential of 5 mV vs. Li/Li⁺,followed by a constant voltage step at 5 mV vs. Li/Li⁺ until a cutoffcurrent of 5 mA/g was reached. 1^(st) discharge: constant current step20 mA/g to a potential of 1.5 V vs. Li/Li⁺, followed by a constantvoltage step at 1.5 V vs. Li/Li⁺ until a cutoff current of 5 mA/g wasreached. Further charge cycles: constant current step at 50 mA/g to apotential of 5 mV vs. Li/Li⁺, followed by a constant voltage step at 5mV vs. Li/Li⁺ until a cutoff current of 5 mA/g was reached. Furtherdischarge cycles: constant current step at 372 mA/g to a potential of1.5 V vs. Li/Li⁺, followed by constant voltage step at 1.5 V vs. Li/Li⁺until a cutoff current of 5 mA/g was reached.

NUMBERED EMBODIMENTS

The present disclosure may be further illustrated by, but is not limitedto, the following numbered embodiments:

-   1. A silicon-carbon particulate composite suitable for use as active    material in a negative electrode of a Li-ion battery, having one or    more of:    -   (i) microporosity of at least 5.0%, optionally no greater than        about 25.0%;    -   (ii) a BJH average pore width of less than about 250 Å; and    -   (iii) a BJH volume of pores of from about 0.05 cm³/g to about        0.25 cm³/g.-   2. The silicon-carbon particulate composite according to embodiment    1, having a BET SSA of equal to or lower than about 400 m²/g and/or    an average particle size of from about 50-2000 Å.-   3. The silicon-carbon particulate composite according to embodiment    1 or 2, having one or more of:    -   (i) a microporosity of from about 5% to about 20%, for example,        from about 8-17%;    -   (ii) a BJH average pore width of from about 75 Å to about 150 Å,        for example, from about 100-150 Å; and    -   (iii) a BJH volume of pores of at least about 0.50 cm³/g, for        example, from about 0.50 cm³/g to about 1.25 cm³/g.-   4. The silicon-carbon particulate composite according to embodiment    3, having:    -   (1) a BET specific surface area (SSA) of from about 100 to about        400 m²/g, for example, from about 200-400 m²/g, or from about        250-350 m²/g, or from about 275-325 m²/g, or from about 275-300        m²/g, or from about 300-325 m²/g; and/or    -   (2) an average particle size of from about 50 Å to about 300 Å,        for example, from about 50-200 Å, or from about 50-150 Å, or        from about 50-100 Å, or from about 75-100 Å, or from about 80-95        Å.-   5. The silicon-carbon particulate composition according to    embodiment 1 or 2, having one or more of:    -   (i) a microporosity of from about 5% to about 15%, for example,        from about 10-15%;    -   (ii) a BJH average pore width of from about 100 Å to about 180        Å, for example, from about 130 Å to about 150 Å, and    -   (iii) a BJH volume of pores of at least about 0.10 cm³/g, for        example, from about 0.10 cm³/g to about 0.25 cm³/g.-   6. The silicon-carbon particulate composite according to embodiment    5, having:    -   (1) a BET specific surface area (SSA) of from about 10 m²/g to        about 100 m²/g, for example, from about 20-80 m²/g, or from        about 20-60 m²/g, or from about 30-50 m²/g, or from about 35-45        m²/g, or from about 40-45 m²/g; and/or    -   (2) an average particle size of from about 250 Å to about 1000        Å, for example, from about 450-850 Å, or from about 500-800 Å,        or from about 550-700 Å, or from about 575-675 Å, or from about        600-650 Å, or from about 620-640 Å.-   7. The silicon-carbon particulate composite according to any one of    embodiments 1-6, wherein the carbon comprises or is natural and/or    synthetic graphite, or a mixture of natural and synthetic graphite,    optionally wherein the natural or synthetic graphite is exfoliated    graphite or expanded graphite.-   8. A silicon-carbon particulate composite having a nanostructure    which inhibits or prevents silicon pulverization and/or maintains    electrochemical capacity when used as active material in a negative    electrode of a Li-ion battery.-   9. A silicon-carbon particulate composite according to any one of    embodiments 1-8, wherein the silicon-carbon particulate composite is    a co-milled composite.-   10. A precursor composition for a negative electrode of a Li-ion    battery, the precursor composition comprising a silicon-carbon    particulate composite according to any one of embodiments 1-9,    comprising a further carbonaceous particulate, optionally wherein    the further carbonaceous particulate comprises at least two    different types of carbonaceous particulate.-   11. The precursor composition according to embodiment 10, wherein    the amounts of silicon-carbon particulate composite and further    carbonaceous particulate are such that the precursor composition    comprises from about 1 wt. % to about 90 wt. % silicon, based on the    total weight of the precursor composition, for example, from about 1    wt. % to about 50 wt. %, or from about 1 wt. % to about 25 wt. %.-   12. The precursor composition according to embodiment 10 or 11,    wherein the BET SSA of the precursor composition is lower than the    BET SSA of the silicon-carbon particulate composite, for example,    equal to or lower than about 10 m²/g.-   13. Negative electrode comprising a silicon-carbon particulate    composite according to any one of embodiments 1-9.-   14. Negative electrode comprising a precursor composition according    to any one of embodiments 10-12.-   15. A Li-ion battery comprising an electrode according to embodiment    13 or 14.-   16. A Li-ion battery comprising a negative electrode which comprises    a silicon-carbon particulate composite, wherein silicon    pulverization does not occur during 1^(st) cycle lithium    intercalation and de-intercalation and/or wherein electrochemical    capacity is maintained after 100 cycles.-   17. A method of making a silicon-carbon particulate composite,    comprising co-milling silicon and carbonaceous starting materials    under wet conditions to produce a silicon-carbon particulate    composite having a nanostructure which inhibits or prevents silicon    pulverization when used as active material in a negative electrode    of a Li-ion battery and/or which maintains electrochemical capacity    of a negative electrode.-   18. The method according to embodiment 17, wherein the silicon    starting material is a micronized silicon particulate having a    particle size of from about 1 μm to about 100 μm, for example, from    about 1 μm to about 10 μm.-   19. The method according to embodiment 17 or 18, wherein the method    comprises one or more of the following:    -   wet-milling in the presence of a solvent, for example, an        aqueous alcohol-containing mixture,    -   wet-milling in a rotor-stator mill, a colloidal mill or a media        mill,    -   wet-milling under conditions of high shear and/or high power        density,    -   wet-milling in the presence of relatively hard and dense milling        media, and drying.-   20. The method according to any one of embodiments 17-19, wherein    co-milling is conducted in the presence of a milling media having a    density of at least 3.0 g/cm³, for example, at least about 5.0    g/cm³.-   21. The method according to embodiment 19 or 20, wherein the milling    media has a particle size of less than about 10 mm, for example,    less than about 1 mmm.-   22. The method according to embodiment 20 or 21, wherein the milling    media is yttria-stabilized zirconia.-   23. The method according to any one of embodiments 17-22, wherein    co-milling is conducted in a bead mill.-   24. The method according to any one of embodiments 17-23, wherein    the power density during co-milling is at least about 2.5 kW/l.-   25. A method of preparing a precursor composition for a negative    electrode of a Li-ion battery, comprising preparing, obtaining,    providing or supplying a silicon-carbon particulate composite    according to any one of embodiments 1-9 or obtainable by a method    according to any one of embodiments 17-24, and combining with a    further carbonaceous particulate.-   26. A method of preparing a precursor composition for a negative    electrode of a Li-ion battery, comprising preparing, obtaining,    providing or supplying a carbonaceous particulate and combining with    a silicon-carbon particulate composite according to any one of    embodiments 1-9 or obtainable by a method according to any one of    embodiments 17-24.-   27. A method of preparing a precursor composition for a negative    electrode of a Li-ion battery, comprising combining a silicon-carbon    particulate composite according to any one of embodiments 1-9 or    obtainable by a method according to any one of embodiments 17-24    with a further carbonaceous particulate.-   28. The method according to any one of embodiments 25-27, wherein    the further carbonaceous particulate is prepared at a first location    and combined with the silicon-carbon particulate composite at a    second location.-   29. A method according to any one of embodiments 25-27, wherein the    further carbonaceous particulate and silicon-carbon particulate    composite are prepared and combined at the same location.-   30. A method of manufacturing a negative electrode for a Li-ion    battery, comprising forming the negative electrode from a precursor    composition according to any one of embodiments 10-12 or obtainable    by a method according to any one of embodiments 25-29, optionally    wherein the precursor composition comprises additional components or    is combined with additional components during forming, optionally    wherein the additional components include binder.-   31. Use of a silicon-carbon particulate composite as active material    in a negative electrode of a Li-ion battery to inhibit or prevent    silicon pulverization during cycling, for example, during 1^(st)    cycle Li intercalation or de-intercalation and/or to maintain    electrochemical capacity after 100 cycles.-   32. Use according to embodiment 31, wherein the silicon-carbon    particulate composite is a silicon-carbon particulate composite    according to any one of embodiments 1-9.-   33. Use according to embodiment 31 or 32, wherein Li is    electrochemically extracted from an amorphous lithium silicon phase    and in the substantial absence of two crystalline phases containing    crystalline Si silicon metal and crystalline Li₁₅S₄ alloy.-   34. Use, as active material in a negative electrode of a Li-ion    battery, of a silicon-carbon particulate composite according to any    one of embodiments 1-9, for improving cycling stability of the    Li-ion battery compared to a Li-ion battery which comprises an    active material which is a mixture of silicon particulate and    carbonaceous particulate which is not a composite and/or does not    have a nanostructure which inhibits or prevents silicon    pulverization during cycling, for example, during 1^(st) cycle Li    intercalation, and/or which is not prepared by co-milling and/or    does not have a nanostructure which maintains electrochemical after    100 cycles.-   35. Use of a carbonaceous particulate material in a negative    electrode of a Li-ion battery, wherein the electrode comprises a    silicon-carbon particulate composite according to any one of    embodiments 1-9.-   36. A device comprising the electrode according to embodiment 13 or    14, or comprising the Li-ion battery according to embodiment 15 or    16.-   37. The device according to embodiment 36, wherein the device is an    electric vehicle or a hybrid electric vehicle, or a plug-in hybrid    electric vehicle.-   38. An energy storage cell comprising a silicon-carbon particulate    composite according to any one of embodiments 1-9 or a precursor    composition according to any one of embodiments 10-12.-   39. An energy storage and conversion system comprising a    silicon-carbon particulate composite according to any one of    embodiments 1-9 or a precursor composition according to any one of    embodiments 10-12.-   40. The energy storage and conversion system according to embodiment    39, wherein the system is or comprises a capacitor, or a fuel cell.

Having described the various aspects of the present disclosure ingeneral terms, it will be apparent to those of skill in the art thatmany modifications and slight variations are possible without departingfrom the spirit and scope of the present disclosure. The presentdisclosure is furthermore described by reference to the following,non-limiting working examples.

EXAMPLES Example 1 Si—C Particulate Composite Formation

Prep A

300 g of micronized silicon particles (1-10 μm), 30 g of an expandedgraphite and 3 g of polyacrylic acid (PAA) were dispersed with 2400 g ofwater and 600 g of isopropanol and milled in a bead mill machine using0.35-0.5 mm yttrium-stabilized zirconia at 3.5 kW/l. The slurry wascollected after 75 min and dried in a spray drier at 70° C. (producingNano-composite 1) or dried in an air oven at 110° C. (producingNano-composite 2).

Prep B

30 g of micronized silicon particles (1-10 μm), 65 g of an expandedgraphite were dispersed with 2400 g of water and 600 g of isopropanoland milled in a bead mill machine using 0.35-0.5 mm yttrium-stabilizedzirconia at 3.5 kW/l for 40 min, and afterwards 200 g of syntheticgraphite having a BET SSA of about 12 m²/g were added and further milledfor 15 min. The slurry was collected (producing Nano-composite 4) ordried in an air oven at 110° C. (producing Nano-composite 3).

SEM pictures of Nano-composite 1 and Nano-composite 3 are shown in FIGS.1A and 1B, respectively. The pore size distributions of Nano-composites1, 2 and 3 are shown in FIG. 2, with this and additional data summarizedin Table 1.

TABLE 1 Nano- Nano- composite 1 composite 2 Nano-composite 3 BET (m²/g)316.0 286.5 41.4 Microporosity (%) 15.7 9.6 12.1 BJH volume of pores1.02 0.84 0.145 (cm³/g) BJH average pore width 133.5 109.9 140.2 (Å)Average Particle Size 82.5 91.1 629.8 (Å)

Example 2

Dispersion formulation A: 2% Super C45 conductive carbon black, 7% CMC(Na-carboxymethyl cellulose) binder, 91% Nano-composite 3

Dispersion preparation: Combined were 0.25 g Super C45, 11.4 g,Nano-composite 3, 70 g water/ethanol mixture (7:3 w/w), then 5 min witha rotor-stator mixer at 16′000 rpm. 0.88 g of the CMC binder was slowlyadded while stirring with a mechanical mixer at 1′000 rpm. Arotor-stator mixer at 16′000 rpm was used for 2 min, and stirred for 30min under vacuum at 1′000 rpm.Dispersion formulation B: 2% Super C45 conductive carbon black, 7% CMC(Na-carboxymethyl cellulose) binder, 91% Nano-composite 4.Dispersion preparation: Combined were 0.25 g Super C45, 91.2 gNano-composite 4, and stirred with a glass rod. 0.88 g of the CMC binderwas slowly added while stirring with the mechanical mixer 1′000 rpm. Arotor-stator mixer at 16′000 rpm for 2 min was used stirred for 30 minunder vacuum at 1′000 rpm.Dispersion formulation C (comparative): 2.38 g (5%) Si particulate (100nm diameter, US Research Nanomaterials Inc.), 45.12 g (90%) graphiteactive material, 0.50 g (1%) Super C45 conductive carbon black, 50.0 g(1.5%) CMC (Na-carboxymethylcellulose) binder solution (1.5% solidcontent in water), 2.6 g (2.5%) SBR (styrene-butadiene rubber) bindersolution (50% solid content in water).Dispersion preparation: To CMC binder solution, were added Super C45conductive carbon black, the Si-particulate, stirred with a glass rod,then stirred with rotor-stator mixer at 11′000 rpm for 5 min. Thegraphite active material and the SBR binder were added and stirred witha mechanical mixer at 1′000 rpm for 30 min under vacuum.Electrode loading on copper electrode: 3 mg/cm². Electrode density: 1.4g/cm³.

Drying procedure: Coated Cu foils were dried for 1 h at 80° C., followedby 12 h at 150° C. under vacuum (<50 mbar). After cutting, theelectrodes were dried for 10 h at 120° C. under vacuum (<50 mbar) beforeinsertion into the glove box. Electrolyte: Ethylenecarbonate(EC):Ethylmethylcarbonate (EMC) 1:3 (v/v), 1 M LiPF₆, 2% fluoroethylenecarbonate, 0.5% vinylene carbonate. Separator: Glass fiber sheet, ca. 1mm.

Electrochemical capacity and cycling stability for each formulation weretested in accordance with the methods described herein.

Cycling performance of the negative electrodes made from Dispersionformulation A (black filled circles), Dispersion formulation B (greyfilled circles) and Dispersion formulation C (open circles) is shown inFIG. 3. 1^(st) cycle lithium intercalation (black curves) andde-intercalation (gray curves) of the negative electrodes are shown inFIG. 4A (Dispersion formulation A), FIG. 4B (Dispersion formulation B)and FIG. 4C (Dispersion formulation C including the commercialSi-particulate).

The de-intercalation curves (FIGS. 4A and 4B) demonstrates the absenceof a plateau at 0.45 V vs. Li/Li⁺ for Nanocomposite 3 and 4, whereas thecommercially available Si-particulate exhibits such a plateau,indicating significant silicon pulverization.

1. A silicon-carbon particulate composite suitable for use as activematerial in a negative electrode of a Li-ion battery, having one or moreof: (i) a microporosity of at least 5.0%, optionally no greater thanabout 25.0%; (i) a BJH average pore width of less than about 250 Å; and(ii) a BJH volume of pores of from about 0.05 cm³/g to about 0.25 cm³/g;wherein the carbon comprises natural graphite synthetic graphite, or amixture of natural and synthetic graphite.
 2. The silicon-carbonparticulate composite according to claim 1, further characterized byhaving one or more of (i) a BET SSA of equal to or lower than about 400m² g; (ii) an average particle size of from about 50-2000 Å; (iii) amicroporosity of from about 5% to about 20%; (i) a BJH average porewidth of from about 75 Å to about 150 Å; and (ii) a BJH volume of poresof at least about 0.50 cm³/g.
 3. The silicon-carbon particulatecomposition according to claim 1, having one or more of: (i) amicroporosity of from about 5% to about 15%; (ii) a BJH average porewidth of from about 100 Å to about 180 Å; (iii) a BJH volume of pores ofat least about 0.10 cm³/g; (iv) a BET specific surface area (SSA) offrom about 10 m²/g to about 100 m²/g; and (v) an average particle sizeof from about 250 Å to about 1000 Å.
 4. A silicon-carbon particulatecomposite having a nanostructure which inhibits or prevents siliconpulverization and/or maintains electrochemical capacity when used asactive material in a negative electrode of a Li-ion battery.
 5. Thesilicon-carbon particulate composite according to claim 1, wherein thesilicon-carbon particulate composite is a co-milled composite.
 6. Aprecursor composition for a negative electrode of a Li-ion battery, theprecursor composition comprising a silicon-carbon particulate compositeaccording to claim 1, and a further carbonaceous particulate, whereinthe further carbonaceous particulate comprises at least two differenttypes of carbonaceous particulate.
 7. The precursor compositionaccording to claim 6, wherein the BET SSA of the precursor compositionis lower than the BET SSA of the silicon-carbon particulate composite,wherein the BET SSA of the precursor composition is equal to or lowerthan about 10 m²/g; and the amounts of silicon-carbon particulatecomposite and further carbonaceous particulate are such that theprecursor composition comprises from about 1 wt. % to about 90 wt. %silicon, based on the total weight of the precursor composition.
 8. Anegative electrode comprising a silicon-carbon particulate compositeaccording to claim
 1. 9. A Li-ion battery comprising an electrodeaccording to claim 8, wherein silicon pulverization does not occurduring 1^(st) cycle lithium intercalation and de-intercalation and/orwherein electrochemical capacity is maintained after 100 cycles.
 10. Amethod comprising co-milling silicon and carbonaceous starting materialsunder wet conditions to produce a silicon-carbon particulate compositehaving a nanostructure that inhibits or prevents silicon pulverizationwhen used as active material in a negative electrode of a Li-ion batteryand/or which maintains electrochemical capacity of a negative electrode;wherein the silicon starting material is a micronized siliconparticulate having a particle size of from about 1 μm to about 100 μm;and wherein the method comprises one or more of the following:wet-milling in the presence of an aqueous alcohol-containing mixture ora solvent, wet-milling in a rotor-stator mill, a colloidal mill, or amedia mill, wet-milling under conditions of high shear and/or high powerdensity, wet-miffing in the presence of relatively hard and densemilling media, and drying.
 11. A method according to claim 10, themethod comprising combining a carbonaceous particulate with thesilicon-carbon particulate composite.
 12. A negative electrode of aLi-ion battery comprising a silicon-carbon particulate compositeaccording to claim 1, wherein the electrode exhibits reduced siliconpulverization during 1^(st) cycle Li intercalation or de-intercalation,the electrode maintains electrochemical capacity after 100 cycles; andLi is electrochemically extracted from an amorphous lithium siliconphase and in the substantial absence of two crystalline phasescontaining crystalline Si silicon metal and crystalline Li₁₅S₄ alloy.13. A negative electrode of a Li-ion battery comprising a silicon-carbonparticulate composite according to claim 1, wherein the electrodeexhibits improved cycling stability of the Li-ion battery compared to aLi-ion battery that comprises an active material which is a mixture ofsilicon particulate and carbonaceous particulate which is not acomposite and/or does not have a nanostructure which inhibits orprevents silicon pulverization during cycling, and/or which is notprepared by co-milling and/or does not have a nanostructure whichmaintains electrochemical after 100 cycles.
 14. (canceled)
 15. A devicecomprising an electrode according to claim 8, wherein the device is anelectric vehicle or a hybrid electric vehicle, or a plug-in hybridelectric vehicle
 16. A device comprising an electrode according to claim8, wherein the device comprises an energy storage cell or an energystorage and conversion system.
 17. The device according to claim 16,wherein the energy storage and conversion system comprises a capacitoror a fuel cell.
 18. The silicon-carbon particulate composite of claim 1,wherein the natural or synthetic graphite is exfoliated graphite orexpanded graphite.